I didn't have an appendectomy, but I did have my gallbladder removed five years ago. This procedure was the trigger point to my now much more geographically spread pain issues.

RSD usually presents in a limb, so I had to go to quite a few doctors to get an idea as to why my arms, legs, face, and back were suddenly on fire one afternoon.

I do so very much hope your pain stays localized to the area you describe. For me, any new trauma, such as twisting my ankle, getting at the time diagnostic nerve blocks, etc. left me with permanent pain, a new burner on the stove turned on, which when flared is an 8, and when not at a beautiful 3 or 4.